/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jena.riot.thrift;

import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;

import org.apache.jena.graph.Node;
import org.apache.jena.riot.thrift.wire.RDF_DataTuple;
import org.apache.jena.riot.thrift.wire.RDF_Term;
import org.apache.jena.riot.thrift.wire.RDF_VAR;
import org.apache.jena.riot.thrift.wire.RDF_VarTuple;
import org.apache.jena.sparql.core.Var;
import org.apache.jena.sparql.engine.binding.Binding;
import org.apache.thrift.TException;
import org.apache.thrift.protocol.TProtocol;
import org.apache.thrift.transport.TIOStreamTransport;
import org.apache.thrift.transport.TTransportException;

/** Converted from Bindings to SPARQL result set encoded in Thrift */
public class Binding2Thrift implements AutoCloseable {
    private final RDF_DataTuple row = new RDF_DataTuple();
    private final Collection<Var> vars;
    private final OutputStream out;
    private final TProtocol protocol;
    private final boolean encodeValues;

    public Binding2Thrift(OutputStream out, Collection<Var> vars, boolean encodeValues) {
        this.out = out;
        this.vars = vars;
        try {
            TIOStreamTransport transport = new TIOStreamTransport(out);
            this.protocol = TRDF.protocol(transport);
        } catch (TTransportException ex) { throw new RiotThriftException(ex); }
        this.encodeValues = encodeValues;
        varsRow();
    }

    private void varsRow() {
        RDF_VarTuple vrow = new RDF_VarTuple(new ArrayList<>(vars.size()));
        for ( Var v : vars ) {
            RDF_VAR rv = new RDF_VAR();
            rv.setName(v.getName());
            vrow.addToVars(rv);
        }
        try { vrow.write(protocol); }
        catch (TException e) { TRDF.exception(e); }
    }

    public Binding2Thrift(TProtocol out, Collection<Var> vars, boolean encodeValues) {
        this.vars = vars;
        this.out = null;
        this.protocol = out;
        this.encodeValues = encodeValues;
        varsRow();
    }

    public void output(Binding binding) {
        Iterator<Var> vIter = (vars == null ? null : vars.iterator());
        if ( vIter == null )
            vIter = binding.vars();
        // ** Java8
//        vIter.forEachRemaining(v -> {
//            Node n = binding.get(v);
//            RDF_Term rt = ( n == null ) ? TRDF.tUNDEF : ThriftConvert.convert(n);
//            row.addToRow(rt);
//        });
        while(vIter.hasNext()) {
            Var v = vIter.next();
            Node n = binding.get(v);
            RDF_Term rt = ( n == null ) ? TRDF.tUNDEF : ThriftConvert.convert(n, encodeValues);
            row.addToRow(rt);
        }
        try { row.write(protocol); }
        catch (TException e) { TRDF.exception(e); }
        row.clear();
    }

    @Override
    public void close() {
        TRDF.flush(protocol);
    }
}
